For example, a glow plug heater of an automobile engine has been known which includes an insulating base, a resistor embedded in the insulating base, and a lead embedded in the insulating base. The lead is joined to the resistor at one end thereof and the other end is led out as a terminal portion on the surface of the insulating base.
More specifically, a known glow plug heater has the structure in which a lead for an anode has at least two bent portions in longitudinal section, and is led out as a terminal portion disposed at, for example, the back end of the insulating base (see, for example, PTL 1). The lead is led out as the terminal portion, keeping the diameter thereof at the two bent portions.